Colouring

I was at a wellbeing fair thing today (yoga and fitness classes and talks) and we went to a well known chain restaurant for lunch. They had colouring in as placemats which i liked since I like to keep my hands busy. I am sure I have read about concentration being better if you're keeping your hands busy because it uses up the bit of your brain that might otherwise become distracted. I need to go and find that and save it to show people who give me odd looks when I doodle.